Embed Size (px)
Citation preview
SUMMARY REPORT: NATIONAL SHOWCASE
SC - 2016 Implementation Assistance Program
Tools to Improve PCC Pavement Smoothness During Construction (R06E)
Seeking widespread adoption of the real-
time smoothness (RTS) technology by
contractors and agencies who routinely
construct PCC pavements will be achieved
through:
1. Equipment Loan Program
2. Showcase
3. Workshops
4. Case studies/results Documentation
5. Specification Refinement
6. Marketing & Outreach
BLANK PAGE
1
INTRODUCTION The Federal Highway Administration (FHWA) has contracted with the National Center for Concrete
Pavement Technology (CP Tech Center) for Implementation Support for Strategic Highway Research
Program II (SHRP2) Renewal R06E Real-time Smoothness Measurements on Portland Cement
Concrete Pavements During Construction. One of the tasks included in this contract is a national
showcase. This task involves providing a showcase/open house in conjunction with a real-time
smoothness equipment loan, with the objective of providing state departments of transportation and
contractors with a better understanding of the benefits of using real-time smoothness equipment to
improve the initial smoothness of concrete pavements.
This report summarizes the activities associated with the national showcase and contains the
following information:
Utah Real-time Smoothness Technology Showcase Agenda (Appendix 1)
Utah Real-Time Smoothness Brochure (Appendix 2)
Utah Project Descriptions for I-215 and I-15 (Appendix 3)
Tech Brief on Real-Time Smoothness Measurements for Portland Cement Concrete
Pavements (Appendix 4)
Attendance Roster (Appendix 5)
RTS Showcase Summary A national showcase for the implementation of real-time smoothness (RTS) technology for concrete
pavements was held in Salt Lake City, Utah on August 9, 2016 (figures 1, 2 and 3). This event is a
part of the SHRP2 implementation effort sponsored by the Federal Highway Administration.
Attendees participated in a half-day workshop which included discussions on: transitioning to
international roughness index (IRI) measurement, contractors’ perspectives on the use of RTS
equipment and best practices for implementing RTS equipment to achieve better initial smoothness
for concrete pavements. Following the morning session, attendees were taken by bus to a project
site where RTS equipment was demonstrated, and questions were answered.
State departments of transportation represented at the showcase included:
Colorado
Florida
Georgia
Louisiana
Nevada
New Mexico
Oklahoma
Utah
Wyoming
2
Total attendance at the showcase was 58, representing FHWA, state DOT’s, contractors and
associated industry participants (Appendix 5).
Figure 1 – Real-Time Smoothness Showcase
Figures 2 and 3 – Utah Real-Time Smoothness Showcase, Attendees at the Project Site
3
Acknowledgements The CP Tech Center team would like to thank the following for their voluntary contribution in making
the National Showcase a success:
UDOT
FHWA
Utah Chapter ACPA
Geneva Rock Products, Inc.
Ralph L. Wadsworth Construction Company, LLC
Appendix 1 – National Showcase Agenda
A1-1
Real-time Smoothness Technology Showcase August 9, 2016
Salt Lake City, Utah
Showcase Agenda
SHOWCASE OBJECTIVES
To introduce agency and contractor personnel to real-time smoothness (RTS) technology for concrete pavement construction.
To hear from users of RTS technology how it can help contractors achieve pavement smoothness requirements.
To provide participants to observe RTS technology in action with site visits to concrete paving projects utilizing RTS systems.
SHOWCASE SCHEDULE
REGISTRATION – 8:00 a.m. – 9:00 a.m.
Morning Program
9:00 a.m. - Welcome from UDOT and FHWA
Randy Park, UDOT and Brigitte Mandel, FHWA Utah Division
9:15 a.m. Overview of RTS Technology and SHRP2 Implementation Program
Gary Fick and David Merritt
10:00 a.m. UDOT perspective on use of RTS technology and transition to IRI smoothness
specification
Jason Simmons, UDOT
10:15 a.m. Break
10:30 a.m. UDOT/Contractor Overview of I-15 Project
Rod Terry and Jace Mecham, UDOT and Scott Preston, Geneva Rock
10:50 a.m. UDOT/Contractor Overview of I-215 Project
Jon Ogden, UDOT and Brian Spahr, Ralph L. Wadsworth
11:10 a.m. Lessons Learned from RTS Equipment Loans
Gary Fick and David Merritt
11:50 a.m. Q&A, Instructions for afternoon site visit
Afternoon Program
Board buses at noon for site visits. Box lunch will be provided.
Site visit to I-215 project in Salt Lake City utilizing RTS equipment. (canceled due to maintenance of traffic restrictions)
Site visit to I-15 project north of Odgen utilizing RTS equipment.
Return to hotel by 5:00 PM
FHWA/SHRP2 CONTACT
Stephen Cooper, FHWA
(410) 962-0629
FOR MORE INFORMATION
http://www.fhwa.dot.gov/goshrp2/Solutions/Renewal/R06E/Tools_to_Improve_PCC_Pavement_Smoothnes
s_During_Construction
Appendix 2 – National Showcase Brochure
A2-1
Appendix 2 – National Showcase Brochure
A2-2
Appendix 3 – Project Information Sheets
A3-1
I-215 PROJECT (Reconstruction Project)
Existing Pavement: 4-lane interstate constructed in 1976; 10” JPCP on 4” lean concrete base
New Pavement: Constructed 2016-2017; 11” JPCP on 3” HMA base (widening into median)
Contractor: Ralph L. Wadsworth Construction Company
Quantities: 11” JPCP – 472,200 S.Y. (Mainline)
10” JPCP - 52,113 S.Y. (Ramps)
Specifications: Table 1 Table 2
Incentives and Disincentives for Category 1 Pavements
MRI Range (inches / mile)
By Pavement Section)
Dollars/Pavement Section
Asphalt Materials
Portland Cement Concrete
≤ 40.0 $750 $1500
40.1 – 50.0 $500 $1000
50.1 – 60.0 $250 $500
60.1 – 70.0 $0 $0
70.1 – 80.0 -$250 -$500
80.1 – 90.0 -$500 -$1000
90.0 Corrective Action
Localized Roughness Limits
Roadway MRI w/base length of 25 ft. (in./mile)
Interstate including ramps ≤ 140
Non-interstate ≤ 160
Urban roadways with speed limits less than 45 mph
≤ 160
Shoulders and Bike Lanes ≤ 190 (IRI for single trace)
Appendix 3 – Project Information Sheets
A3-2
I-15 PROJECT (4-lane Interstate Widening Project into Median)
Widening Section: 9" JPCP on 3” HMA base (widening into median)
Contractor: Geneva Rock Products
Quantities: 300,000 S.Y.
Specifications:
Table 1 Table 2
Incentives and Disincentives for Category 1 Pavements
MRI Range
(inches / mile) By Pavement
Section)
Dollars/Pavement Section
Asphalt Materials
Portland Cement Concrete
≤ 40.0 $500 $1000
40.1 – 50.0 $300 $500
50.1 – 60.0 $150 $250
60.1 – 70.0 $0 $0
70.1 – 80.0 -$150 -$250
80.1 – 90.0 -$300 -$500
90.0 Corrective Action
Localized Roughness Limits
Roadway MRI w/base length of 25 ft. (in./mile)
Interstate including ramps ≤ 140
Non-interstate ≤ 140
Urban roadways with speed limits less than 45 mph
≤ 160
Shoulders and Bike Lanes ≤ 175 (IRI for single
trace)
Appendix 4 – Real-Time Smoothness Tech Brief
A4-1
Tech Brief on Real-Time Smoothness Measurements for Portland Cement Concrete Pavements
Introduction
Pavement smoothness is one of the most important factors affecting user (driver) satisfaction. As far
back as the AASHO Road Test it has been recognized that road users judge the quality of a road
primarily based on its ride quality. However, initial smoothness of a portland cement concrete
pavement (PCCP) also has a direct impact on the life of the pavement. According to the findings of
Perera, et al. (1), “… pavements that are built smoother will provide a longer service life before
reaching a terminal roughness value, compared to pavements having a lower initial smoothness
level.” Therefore, from both a user and a life cycle cost perspective, it is desirable to construct smooth
PCC pavements. The use of real-time smoothness equipment can assist the contractor in improving
the initial smoothness of PCCP.
Real-Time Smoothness (RTS) Systems
There are currently two systems commercially available for measuring PCCP smoothness in real-
time: Ames Real-Time Profiler (RTP) (Figure 2), and Gomaco Smoothness Indicator (GSI). Both are
configured similarly with sensors mounted to the back of the paver to measure the pavement profile
and send it to the data collection hardware and software for processing and display in real-time
(figure 1). The primary difference between the systems is the sensor technology used, the GSI uses
acoustic (ultra-sonic) sensors and the RTP uses lasers. When mounted to the back of the paver, both
systems capture profile data by measuring the height of the sensor relative to the fresh pavement
directly behind the paver (typically 6” to 12” behind the pan or trailing pan). Both systems use a
combination of height, slope and distance data which is continuously fed to the software where it is
converted to a real-time profile and smoothness statistics (IRI, PI, must grinds and localized
roughness). Distance data is collected using a calibrated bicycle wheel, a wheel mounted to a paver
track or an internal encoder.
Figure 1. Diagram of a Real-Time Smoothness System
Ames Real-Time Profiler (RTP)
The Ames unit is a laser based sensor combined with a ruggedized laptop (figure 2).
Figure 2. Ames RTP System Installed on a Paver (from the left: RTP sensors mounted at the back of the
paver, computer showing real-time smoothness information and bicycle wheel collecting distance data)
Appendix 4 – Real-Time Smoothness Tech Brief
A4-2
Gomaco GSI
The Gomaco unit uses sonic sensors and a dedicated computer (figure 3).
Figure 3. Gomaco GSI System Installed on a Paver (from the left: GSI sensors mounted at the back of the
paver, computer showing real-time smoothness information and wheel mounted to the paver track collecting
distance data)
Each of these systems underwent a thorough independent evaluation as part of the SHRP2 R06E
project Real-Time Smoothness Measurements on Portland Cement Concrete Pavements During
Construction (2). Findings from this project concluded that both systems demonstrated their value
as a quality control (QC) tool for the contractor in assessing initial pavement smoothness and
providing real-time feedback for process adjustments. Based on these findings, the Federal Highway
Administration (FHWA) nominated this technology for SHRP2 implementation funding. In cooperation
with FHWA, The National Concrete Pavement Technology Center (CP Tech Center) has been involved
in furthering the implementation of real-time smoothness by exposing contractors to the technology
through equipment loans and through workshops designed to help contractors realize the benefits of
this tool for improving the initial smoothness of PCCP.
Benefits of Using Real-Time Smoothness Systems
When properly implemented into the contractor’s paving operation, real-time smoothness systems
provide valuable feedback which allows the contractor to adjust their processes to improve the initial
smoothness characteristics (overall smoothness and localized roughness) of the new PCCP. While
profilographs and lightweight inertial profilers have traditionally been used for quality control and
quality assurance (acceptance level) smoothness measurements. The pavement must have adequate
strength and all sawing must be completed before they can be operated on the pavement surface,
resulting in a minimum 12 to 24 hour delay in the feedback on smoothness numbers. Real-time
smoothness systems provide the same profile information as the profilograph and inertial profiler,
but in real-time during paving. It should be noted that these systems are not intended for and should
not be used for acceptance measurements. (See Real-Time IRI vs. Hardened IRI for further details
– Page 4). However, having this information in real-time allows the contractor to make process
adjustments sooner and allows for corrections to be made during finishing, providing the contractor
the opportunity to construct smoother pavements.
The primary process adjustments that can be validated by use of these systems include but are not
limited to:
Tuning the paver – there are numerous adjustments and operational characteristics of slipform
pavers which impact pavement smoothness (see the following section for more detail).
Mixture adjustments aimed at improving the overall workability and/or edge stability.
In addition, localized roughness caused by major profile events (e.g. loss of vertical control, paver
stops, etc.) resulting in dips and bumps which need to be corrected by hand finishing, can be
Appendix 4 – Real-Time Smoothness Tech Brief
A4-3
identified using real-time smoothness systems. The effectiveness of the correction made by hand
finishing is a matter of workmanship, there is no real-time verification for this process.
The power of these systems to improve the initial smoothness of PCC pavements lies in the timely
use of profile information. No improvement to smoothness occurs by installing a system on a paver;
improvements are only possible when the crew members embrace the technology and act on the
feedback provided in real-time.
Using Real-Time Smoothness Systems
Through the experience gained from the equipment loans, the CP Tech Center team has developed
recommendations for contractors who are interested in using these systems. This four step
implementation process includes:
1) Establish a baseline – monitor the process.
a. Install a real-time smoothness system.
b. Monitor results for 1 to 2 days.
c. Keep processes static, but make ordinary adjustments (mixture, vibrators, paving
speed, head, etc.).
d. Observe typical responses to the ordinary adjustments and make notes or add event
markers in the RTS.
2) Eliminate large events – actively utilize the real-time system to reduce the impact of major
profile features.
a. Stringline/stringless interference.
b. Paver stops.
c. Padline issues.
d. Other mixture or process impacts.
3) Fine-tune the paving process – utilize the real-time feedback when making intentional
adjustments to the processes.
a. Paver adjustments.
i. Maintaining/adjusting concrete head in the grout box.
ii. Adjusting the angle of attack of the paver – setting the longitudinal profile of
the slipform mold as flat as practical relative to the roadway profile.
iii. Hydraulic and stringless sensitivities.
iv. Vibrators (height and frequency).
v. Paving speed.
b. Concrete mixture adjustments to improve overall workability, finishing properties
and/or edge stability.
i. Aggregate proportions.
ii. Admixture dosages.
iii. Water:cementitious materials (w/cm) ratio (note: w/cm should never be
adjusted above the approved mix proportions).
iv. Total mass of cementitious materials.
v. Ratio of supplementary cementitious materials to portland cement.
4) Identify repeating profile features using the power spectral density analysis (PSD) in ProVAL
and use the real-time system to mitigate the roughness from these features. The PSD function
of road profiles is a statistical representation of the importance of various wavelengths. It
provides valuable information regarding what repeating wavelengths are contributing to
pavement roughness.
a. Doweled joints.
b. Dumping/Spreading loads.
c. CRCP bar supports.
Appendix 4 – Real-Time Smoothness Tech Brief
A4-4
Lessons Learned from Real-Time Smoothness Equipment Loans
Six real-time smoothness equipment loans have been completed by the CP Tech Center as part of
the SHRP2 Technology Implementation program. A sampling of the lessons learned from utilization
of the real-time smoothness systems on these projects in Idaho, Iowa, Nebraska, Michigan,
Pennsylvania and Texas shows the potential benefit of utilizing real-time profile feedback.
Pennsylvania
This real-time smoothness equipment loan took place in October/November of 2015 on the
northbound lanes of I-81 near Pine Grove, PA (figure 4), the Gomaco GSI was utilized. Paving was
24’ wide and consisted of two typical sections: 8” thick JPCP unbonded overlay and 13” thick JPCP
reconstruction sections.
Figure 4. Paving on I-81 in Central PA
Real-Time IRI vs. Hardened IRI
It should be noted that for multiple reasons and in almost all cases, the IRI measured by real-time
smoothness equipment will be higher than when the hardened slab is measured by an inertial profiler.
This difference does not invalidate the real-time measurements, users should simply focus on making
the real-time IRI lower and the hardened IRI will follow (initial pavement smoothness is improved).
The project on I-81 provided good examples of the properties of real-time and hardened profiles.
Figure 5 shows the profile data for a section of I-81 from September 28, 2015 where the real-time
IRI is 20 in/mile greater than the hardened IRI measured using a lightweight inertial profiler. Even
though the IRI results between real-time and hardened profiles are different, the data shows that
they parallel each other closely, indicating that the difference is not entirely due to RTP measurement
error.
Appendix 4 – Real-Time Smoothness Tech Brief
A4-5
Figure 5. Comparison of Real-Time Profile (GSI) and Hardened Profile (I-81)
Building upon the previous observations a power-spectral-density (PSD) plot from 28SEP2015
(figure 6) shows differences between the wavelengths contributing to roughness in the passing
lane for the GSI real-time data and hardened data. Peaks shown in PSD plots identify the
wavelengths associated with pavement roughness and do not correlate directly to IRI values. The
following observations can be made from this PSD analysis:
i. Shorter wavelength roughness in the hardened profile is likely from macrotexture (burlap
drag and tining) applied behind the GSI sensors.
ii. Real-time roughness at the 5’ wavelength was significantly reduced by hand finishing.
iii. Joint spacing had a larger influence on roughness in the hardened profile than in the real-
time profile, this is likely a result of curling and warping of the slabs.
iv. The source of roughness present in the hardened profile at longer wavelengths needs
additional investigation.
For this project, the majority of the differences between real-time and hardened profiles can be
attributed to hand finishing, measurement error and slab curling/warping. Each project is unique,
these differences should be analyzed to help identify areas for improvement on a project-by-project
basis.
GSI ProfileHardened Profile
Distance (ft)
Elev
atio
n (
in)
Appendix 4 – Real-Time Smoothness Tech Brief
A4-6
Figure 6. PSD Analysis of Real-Time Profile (GSI) and Hardened Profile
Idaho
Taking place in April of 2015, this equipment loan utilized an Ames RTP on I-84 in Boise, Idaho. The
typical section was 12” thick JPCP, paving was 24’ wide (figure 7).
Figure 7. Paving on I-84 in Boise, ID
Truck Load Influence
On April 21st, the RTP picked up a ~10.5’ feature that was determined to be related to concrete load
spacing which averaged 10.6’ (with a standard deviation of 2’). This feature was also reflected in the
hardened profile, and was more dominant than the joint spacing in the PSD plot. This content was
not noticeable for any of the other days of paving. A PSD analysis from first part of April 21st is
provided in Figure 8.
Wavelength (ft)
Slo
pe
Spec
tral
Den
sity
(ft
/cyc
le)
GSI ProfileHardened Profile
Appendix 4 – Real-Time Smoothness Tech Brief
A4-7
Figure 8. PSD Analysis of Real-Time Profile (GSI) and Hardened Profile
Nebraska
A project on I-80 on the west side of Lincoln, Nebraska utilized an Ames RTP for a real-time
smoothness equipment loan. The typical section consisted of 13” thick JPCP, paving was 24’ wide
(figure 9).
Figure 9. Paving on I-80 in Lincoln, NE
Influence of Concrete Head
May 11th was the first day of paving on I-80 where the RTP was used. As a matter of practice, the
CP Tech Center team requests that the contractor leave their operations unchanged for the first day
while they familiarize themselves with operating the RTP. The next day of paving was May 13th, and
the contractor made an effort to maintain a consistent and smaller head of concrete in front of the
paver than was observed on May 11th. Figure 10 shows continuous IRI results (25’ segment length)
10.5’
Wavelength (ft)
Slo
pe
Spec
tral
Den
sity
(ft
/cyc
le)
RTP ProfileHardened Profile
Appendix 4 – Real-Time Smoothness Tech Brief
A4-8
for both days (the red line is an arbitrary action limit of 125 in/mi). The results from May 13th showed
a 20% reduction in IRI despite the fact that it was only 400’ long.
Figure 10. IRI Localized Roughness (25’ base length) Showing Smoother Pavement Related to a Smaller and
More Consistent Head of Concrete.
Conclusion
Given that concrete pavements which are constructed smoother stay smoother longer, efforts should
be taken to improve the initial smoothness of newly constructed PCC pavements. The use of real-
time smoothness equipment during construction provides valuable information to the contractor
regarding initial smoothness and because the feedback is instantaneous, this gives them confidence
(lowers the risk) to adjust their processes to achieve smoother PCC pavements. Ultimately, the use
of tools such as RTS will help contractors and agencies save money and improve the user satisfaction.
For more information, contact:
Gary Fick, trinity construction management services, inc. – [email protected]
Dave Merritt, The Transtec Group, Inc. – David Merritt [email protected]
Stephen Cooper, Federal Highway Administration - [email protected]
References
1. Perera R., Kohn S., and Tayabji S., Achieving a High Level of Smoothness in Concrete
Pavements Without Sacrificing Long-Term Performance, Soil and Materials Engineers, Inc.
Final Report for FHWA project No. DTFH61-01-C-00030, FHWA, 2005.
2. Rasmussen R., Torres H., Sohaney R., Karamihas S., Fick G., Real-Time Smoothness
Measurements on Portland Cement Concrete Pavements During Construction, The Transtec
Group, Inc. Final Report for SHRP2 project No. R06E, TRB, 2013.
5-11-15 IRI = 124 in/mi
5-13-15 IRI = 98 in/mi
Distance (ft)
IRI (
in/m
i)
Appendix 5 – National Showcase Attendance Roster
A5-1
Attendees for the Utah Real-Time Smoothness Showcase
# First Last Organization # First Last Organization
1 Robert Allred Kiewit 30 L. Scott Nussbaum Utah DOT
2 Jennifer Atkinson Leidos 31 Jon Ogden Utah DOT
3 Steven Anderson Utah DOT 32 Robert Orthmeyer FHWA
4 Kelly Barrett Utah DOT 33 Randy Park Utah DOT
5 Gary Black Utah DOT 34 Robbie Pope Wadsworth
6 Jeremy Bown Utah DOT 35 Scott Preston Geneva Rock
7 Mark Brenner GOMACO 36 Eric Prieve Colorado DOT
8 Glen Clark Utah DOT 37 Matt Romero Oklahoma DOT
9 Zachary Collier Louisiana DOT 38 Bob Rothwell Wyoming DOT
10 Stephen Cooper FHWA 39 PJ Roubinet Utah DOT
11 Jeremy Covington Utah DOT 40 Kenny Seward Oklahoma DOT
12 Josey Dewsnup Ash Grove 41 Brady Shakespear Utah DOT
13 Danny Erickson Utah DOT 42 Jason Simmons Utah DOT
14 Gary Fick Trinity
Construction
43 Mike Smith Forta Corp
15 James Gallego New Mexico DOT 44 Brian Spahr Wadsworth
16 James Greene Florida DOT 45 Scott Strader Utah DOT
17 Steven Hale Nevada DOT 46 Rod Terry Utah DOT
18 Richard Hewitt Florida DOT 47 Adam Triolo AUI Inc
19 Bryon Jones Oklahoma DOT 48 Abdul Wakil Utah DOT
20 Jon Klatt Ames Engineering 49 Jason Waters Georgia DOT
21 Gary Kuhl Utah DOT 50 Matthew Wood Ash Grove
22 Bryan Lee Utah DOT 51 Tom Yu FHWA
23 Brigitte Mandel FHWA 52 Paul Ziman FHWA
24 Jeff Mann New Mexico DOT 53 Robert Stewart Utah DOT
25 Lonnie Marchant Utah DOT 54 Steve Park Utah DOT
26 Mitzi McIntyre UT ACPA 55 Betty Purdi RLW
27 Jace Mecham Utah DOT 56 Cody Preston Genen
28 David Merritt Transtec 57 David Gill Utah DOT
29 Tim Nash Wirtgen America 58 Chris Whipple Utah DOT
